This invention relates to a machining control method in a machine tool capable of performing a first routine of machining toward a workpiece at one spindle side and performing a second routine of machining in such a manner that a workpiece is delivered to the other spindle side while both spindles are synchronously rotated after the machining in a machine tool having the first and the second spindles facing toward each other.
In a case where first and second routines of machining are usually performed on a workpiece on a machine tool having two opposed spindles, such as a lathe, a workpiece is installed on one spindle. In this state, the first routine of machining is performed on the workpiece, and the machined workpiece, after the first routine, is delivered to the other spindle for performance of the second routine of machining. In a conventional method, when a workpiece is delivered, the rotation of the spindle holding the machined workpiece after the first routine is temporarily stopped. In this state, the workpiece after the first routine is detached form the spindle by means of a handling robot or the like. Furthermore, the workpiece is transferred to the other spindle for attachment to the spindle.
To stop the rotation of a spindle whenever a workpiece is delivered is so inconvenient that it takes many hours to deliver a workpiece, since the machined workpiece after the first routine cannot be detached by means of a robot or the like until the spindle stops completely. And in order to perform the second routine of machining after the workpiece detached from the spindle is attached to the other spindle, it is necessary that the rotation number of the other spindle is increased up to a predetermined rotation number necessary for performing machining on a workpiece from a stopped state. Therefore, such inconvenience is present that it takes a long time to perform the second routine of machining.
In consideration of the above-described circumstances, the object of this invention is to provide a machining control apparatus and method in a machine tool capable of performing the first routine of machining by holding a workpiece with one spindle between the opposed spindles, and performing the second routine of machining in such a manner that the workpiece is delivered to the other spindle without stopping the rotation of the spindle after the first routine of machining.